Daytime sleepiness shapes health-related quality of life response to CPAP in obstructive sleep apnea

Abstract Improvements in health-related quality of life (HRQoL) after continuous positive airway pressure (CPAP) therapy vary widely among patients with obstructive sleep apnea (OSA). Excessive daytime sleepiness (EDS) may influence patient-reported outcomes beyond traditional disease severity metrics. We investigated whether baseline EDS modifies HRQoL responses to CPAP in patients with coronary artery disease (CAD) and OSA. We analyzed 1-year changes in HRQoL among CPAP-treated CAD patients with moderate-to-severe OSA (apnea–hypopnea index ≥ 15 events/h) from the RICCADSA cohort. Patients were classified as sleepy (Epworth Sleepiness Scale ≥ 10) or nonsleepy. HRQoL was assessed at baseline and after 1 year using the SF-36. Between- and within-group changes were examined, and multivariable linear regression models evaluated associations between CPAP usage and HRQoL changes. The study included 228 patients (126 sleepy, 102 nonsleepy). At baseline, patients with EDS had significantly lower physical and mental component summary scores and greater impairment across several SF-36 domains. After 1 year of CPAP therapy, improvements were observed in selected domains in both groups; however, patients with EDS continued to report lower mental and psychosocial scores. Baseline SF-36 scores were the strongest predictors of HRQoL change, whereas CPAP usage was not independently associated with improvements. HRQoL responses to CPAP therapy in patients with CAD and OSA were heterogeneous and strongly influenced by baseline daytime sleepiness. EDS identifies a subgroup with greater baseline impairment and persistent residual deficits despite treatment, highlighting the clinical relevance of symptom burden beyond apnea severity when interpreting patient-centered outcomes.